Wyniki wyszukiwania - BazTech

1

A Bipartite Graph for Estimating Measurement Uncertainty on Five-Axis Machining Centres

Stryczek Roman

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 6

449--464

EN

The essential source of errors in machining on five-axis milling centres are errors caused by the improper calibration of a machine tool, setup errors and a process plan which is not designed optimally. For the multilateral machining of the complex, precise parts of machines, a process plan should include, before and during the process, coordinate measurements by means of a touch probe in order to verify previously made surfaces or to determine accurately the position and orientation of a local coordinate system. The uncertainty of these measurements is connected with the estimate precision of performing the manufactured parts. This paper presents a tool devised for determining the uncertainty of the results of coordinate measurements by a simulation method, which is also useful at the stage of machine tool calibration. A basis of this method is a bipartite graph with a tree structure. Transitions in the graph constitute a set of elementary measurement activities and analytical activities which determine the uncertainty of the position and orientation of respective geometric features and abstract objects. Based on the results of the conducted simulation tests it is possible to build analytical models for the rapid determination of measurement uncertainty. The tool devised is aimed at vector dimensioning and therefore it enables simple extension, including integration with geometric dimensioning and tolerancing. This paper includes an example of applying the method devised, which confirms its practicability.

2

Pomiar zużycia energii w trakcie cyklu wiercenia termicznego

Błaszczak Paweł, Stryczek Roman

Pomiary Automatyka Robotyka

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2023

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R. 27, nr 1

93--98

PL

Praca przedstawia zagadnienie dotyczące pomiaru i analizy zużycia energii w trakcie cyklu wiercenia termicznego. Przedstawiono oparte na tokarce CNC stanowisko badawcze, którego elementem wyposażenia był eksperymentalny układ poboru energii oparty o licznik energii elektrycznej oraz siłomierz. Zastosowane urządzenia pomiarowe pozwalały na rejestrację obciążenia sieci energetycznej, obciążenia napędów obrabiarki, siłę osiową, moment hamujący wiertło, aktualne obroty wrzeciona obrabiarki, pozycję wiertła względem obrabianego materiału i wartości rejestrów parametrów pomocniczych w strategii adaptacyjnego sterowania posuwem. Rozważano dwa przypadki cyklu wiercenia: wykonanie pojedynczego otworu oraz wykonanie szeregu otworów w jednym cyklu. Testowano pięć strategii sterowania posuwem w trakcie cyklu wiercenia, w tym adaptacyjne sterowanie posuwem i rekurencyjną metodę optymalizacji posuwu. Dla porównania wykonano także otwory tradycyjnymi wiertłami krętymi HSS. Na podstawie uzyskanych rezultatów badań można stwierdzić, że metoda wiercenia ciernego może być zaliczona do energooszczędnych metod wykonywania otworów w elementach cienkościennych.

EN

The work presents the issue of measuring and analyzing energy consumption during a thermal drilling cycle. A research stand based on a CNC lathe was presented, the equipment of which was an experimental energy consumption system based on an electricity meter and a force gauge. The measuring devices used allowed for recording the load on the power grid, the load on the machine tool drives, the axial force, the drill braking torque, the current rotation of the machine tool spindle, the position of the drill in relation to the workpiece and the values of auxiliary parameter registers in the strategy of adaptive feed control. Two cases of a drilling cycle were considered: making a single hole and making a series of holes in one cycle. Five feed control strategies were tested during the drilling cycle, including adaptive feed control and a recursive feed optimization method. For comparison, holes were also made with traditional HSS twist drills. Based on the obtained test results, it can be concluded that the friction drilling method can be included in the energy-saving methods of making holes in thin-walled elements.

3

Modeling the Work of Multi-spindle Machining Centers with the Petri Nets

Stryczek Roman

Management and Production Engineering Review

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2023

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Vol. 14, No. 3

16--26

EN

The article presents the results of the simulation studies concerning the impact of random production interruptions on the efficiency of multi-spindle machining centers. Four different machining center configuration models were developed using a dedicated class of stochastic Petri nets. In addition to the number of machine spindles, the number of simultaneously mounted parts, loading time of parts, their machining time, and reliability parameters regarding the frequency of machine interruptions caused by random factors were also taken into account as model parameters. A series of virtual tests was carried out for machining processes over a period of 1000 hours of operation. Analysis of the results confirmed the purpose of conducting simulation tests prior to making a decision regarding the purchase of a multispindle milling center. This work fills the existing research gap, as there are no examples in the technical literature of evaluating the effectiveness of multi-spindle machining centers.

4

Method of Selecting a Rational Strategy in Sustainable Friction Drilling

Stryczek Roman, Błaszczak Paweł

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 3

330--332

EN

The presented paper contains a description of a new method of determining the optimum feed rate for a waste-free, energy-efficient drilling process being a friction drilling. Previous experience has shown that the energy required to drill a hole by friction drilling is closely correlated with the drilling cycle time. Based on the authors' own experience, the thesis was put forward that the optimum feed rate during the drilling procedure should be variable but smooth. Additional evaluation criteria for the developed method were the drilling cycle time, the maximum values of the axial force and torque, the maximum values of the feed drive and machine spindle drive load, as well as the energy consumption. The test rig was based on a numerically controlled machine tool, equipped with an axial force and torque sensor, and additional dedicated measuring devices for measuring energy consumption. The results of the study indicate the high competitiveness of the developed approach, compared to the feed rate control strategies in a friction drilling cycle known from the literature. The proposed approach for selecting the longitudinal feed rate can quickly gain a significant number of applications. Studies have shown that optimally planned feed rates can reduce energy intensity by up to 47%.

5

Simulation tests of adaptive control strategies for CNC machine tools

Stryczek Roman, Szczepka Wojciech

Journal of Machine Engineering

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2019

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Vol. 19, No. 2

73--82

EN

The issue addressed in the article concerns the current needs and possibilities of computer-aided design of adaptive control strategies in machining processes. A simulative method of selecting the adaptive feed control strategy while rough turning materials difficult to machine, effective and inexpensive in its implementation, based on controlling the load placed on the machine's drives, has been presented. The results of a number of virtual tests of the proposed feed control strategy have been included, while paying particular attention to the stability of the machining process during moments of sudden change in the machining allowance. The obtained results meet the accepted quality indicators of the control algorithm. At the same time, the experiences collected by the author while conducting the tests confirmed the complexity of the issue and the resulting necessity to implement a comprehensive simulation testing program.